Socially induced tactic change in 2 types of sand goby sneaker males

• Male alternative reproductive tactics, like satellite or sneaking tactics, typically parasitize reproductively on a larger resource-holding tactic. In the sand goby, Pomatoschistus minutus, 2 types of sneaker males are known. Sneaker males with melanization, a typical male breeding coloration, have small testes and large sperm-duct glands, and sneaker males without melanization have large testes and small sperm-duct glands. We tested their potential to change into the nest-holding tactic experimentally by keeping them with or without a large nest-holding male. With nest-holding males, neither sneaker male type built nests. However, without nest-holding males, a large proportion of both types of sneaker males built nests and became nest-holders, and all the nest-building nonmelanized sneaker males developed melanization. Furthermore, nest-building nonmelanized sneaker males had larger sperm-duct glands (used to produce a sperm-containing mucus) than nonnest-building nonmelanized sneaker males. However, contrary to our expectation, treatment did not affect testes size. Compared with melanized sneaker males nonmelanized sneaker males tended to have a lower proportion of nest-building males and showed significantly less reproductive activity, especially in the early experimental period. Finally, in a separate experiment, we confirmed that nonmelanized sneaker males that build nests can spawn and tend eggs normally. Taken together, our results suggest that these tactics are not genetically or ontogenetically fixed but condition dependent. However, this does not exclude an underlying genetic variation in phenotype expression.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

alternative reproductive strategies

bourgeois

genetic polymorphism

Gobiidae

seminal vesicles

alternative mating tactics

zosterisessor-ophiocephalus teleostei

gobius-niger teleostei

male bluegill sunfish

pomatoschistus-minutus

reproductive strategies

genetic-polymorphism

sperm competition

grass

goby

phenotypic plasticity

borsky m

1994

advances in the study of behavior

vol 23

v23

p1

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)